Field of the Invention
Example embodiments relate generally to nuclear reactors, and more particularly to a method and apparatus for a Boiling Water Reactor (BWR) jet pump inlet mixer compliant stop clamp assembly that applies a controlled lateral force to an inlet mixer.
Related Art
A reactor pressure vessel (RPV) of a boiling water reactor (BWR) typically has a generally cylindrical shape and is closed at both ends (for example by a bottom head and a removable top head). A top guide typically is spaced above a core plate within the RPV. A core shroud, or shroud, typically surrounds the core and is supported by a shroud support structure. Particularly, the shroud has a generally cylindrical shape and surrounds both the core plate and the top guide. There is a space or annulus between the cylindrical reactor pressure vessel and the cylindrically shaped shroud.
In a BWR, hollow tubular jet pumps positioned within the shroud annulus provide the required reactor core water flow. The upper portion of the jet pump, known as the inlet mixer, is laterally positioned and supported against two opposing rigid contacts within jet pump restrainer brackets by a gravity actuated wedge.
Conventionally, set screw gaps may be formed by movement of either the main wedge or the inlet mixer. Additionally, vibration may cause wear of the main wedge and/or set screws. Set screw gaps allow the inlet mixer to experience flow induced vibration (FIV), causing excessive wear to jet pump components. Furthermore, the conventional jet pump assembly may also experience slip joint leakage (i.e., leakage between the mechanical connection of the inlet mixer and diffuser).